1. Field of the Invention
The present invention is related to the field of carton handling apparatus, and more particularly to apparatus for automatically opening the flaps of an unsealed, closed carton.
2. Description of the Prior Art
The bottling and packaging industry has long utilized machinery for automatically opening the flaps of cartons and propelling the opened cartons along a delivery conveyor for other operations, such as automatically removing empty containers from the cartons, packing a finished product in the carton, and automatically closing the flaps of the carton. The present invention is concerned with an apparatus which automatically prepares a closed carton by opening the flaps of the carton and disposing them outward so that the interior of the carton is easily accessible for removing or placing material in the carton.
Various types of mechanisms have been devised to open each of the flaps of a box as it moves through, or is stationary on, a delivery conveyor. Perhaps the most difficult flap to open, in terms of the complexity of apparatus required, is the front lateral flap of the box, (e.g. "front" relative to the motion of the carton on the delivery conveyor). The front flap must be opened by a force in the direction of the carton movement; thus a passive element such as a simple plow or hook mechanism which remains stationary cannot be used.
One type of device utilized to open the front flap, U.S. Pat. No. 2,918,773, issued to Krupp et al, is an apparatus comprising a pair of endless chains reeved around sprockets for movement parallel to the delivery conveyor. A rod is attached to corresponding links in each chain and extends outwardly over the carton to engage the flap of the box when the flap has been momentarily lifted by an air jet discharging into the carton. The chain is driven at a lateral speed faster than the movement of the carton on the delivery conveyor, so that the flap is urged forward by the movement of the rod and chain mechanism, thereby opening the flap. However this type of apparatus suffers from the limitation that a means for initially lifting the front flap of the carton must be provided so that the rod attached to the chain will have an initial position on the flap to urge the flap forward, since that rod can be disposed no lower than the top of the carton sides. The apparatus disclosed in U.S. Pat. No. 2,918,773 accomplishes the initial lifting of the flap by directing a stream of air under the flap and into the carton interior, thereby urging the flap upward by the air pressure.
Another method for initially lifting the front flap so that a moving rod or roller can engage the underside of the flap is disclosed by U.S. Pat. No. 3,019,924, issued to Krupp et al. A telescoping spear impales the flap, and further movement of the case through the conveyor system lifts the flap slightly but does not completely open the flap. Still another example of a method for opening a front flap of a box is disclosed by U.S. Pat. No. 3,224,165, issued to Nigrelli et al. Nigrelli utilizes suction cups, selectively activated by application of a vacuum to the cups, which engage the front flap and initially lift the flap so that the typical endless chain mounted rod may engage the underside of the front flap to complete the opening process. Each of the above described apparatus suffers from the limitation that not only must an endless chain mechanism be provided for opening the flap, but also another apparatus for initially lifting the front flap above the level of the carton sides must be provided, which adds to the complexity and expense of the apparatus. Further, not only must additional apparatus be provided, but the action of the initial flap opening mechanism must be synchronized both with the carton movement and the means for completing the flap opening. Another disadvantage of both Krupp et al patents is that an endless chain is mounted on both sides of the box for suspending the rod and disposing it under the front flap, further complicating the apparatus.